Automatic variable pitch propeller



Ju e 6, 1933.

I C. W. LAMBERT AUTOMATIC VARIABLE PITCH PROPELLER Filed June 27, 1932 M W W Patented June 6, 1933 CHANDLEY WILLIAM LAMBERT, F CLEVELAND, OHIO AUTOMATIC VARIABLE PITCH PROPELLER Application filed June 27, 1932. Serial No. 619,481.

. the propeller The invention relates to improvements in automatic variable pitch propellers, using engine power to change the pitch, controlled by balance springs and a fluid pressure plate.

The invention relates to former application Serial Number 462,877, filed June 21, 1330, -now Patent 1,874,053 dated Aug. 30, 1 32. I

Fig. 1 is a vertical cross-sectional view lenFgthwise of the drive shaft.

ig. 2 is an end view of a portion of the actuating mechanism. a

The drawing is alongit udinalcross sec-. tion of one form of the invention, and since the device should be balanced, only one of the similar halves is shown.

In the drawing, 1 represents the crankcase or fuselage, or part of a conveyance from which the propeller shaft 2 projects. 3 is a ropeller hub secured to shaft 2, as shown y lock nuts 4-4. The shank of a propeller blade is shown at 5, to which is secured a worm gear at 6. At 7 is represented aworm gear cooperating with gear 6. Worm gear 7 and gear 9 are secured to shaft 8. Worm gear 10, cooperatin with 9, is secured to the same shaftas beve gear 12 on the opposite side of frame or housing 11 which is secured to hub 3 and shaft 2.

It is worthy of note that forces acting on blade can not turn the worm ears 7 and 10, and the device is nonreversible 1n the same sense that an automobile steerin gear is nonreversible. T

3evel ears 13 and 14 are held in constant mesh with gear 12 by idler pulleys 15 and 16.

17 and 18 are clutch parts secured to gears 13 and 14 respectively, and may engage the other clutch parts 19 or 20 secured to collar 21 which is secured to revolved by gear "23 cooperating with gear 24 on shaft 25, which has a suitable bearing in or on hub 3, and to which gear 26 is attached. Gear 26 cooperates with gear 27 which is secured to chassis 1. I

- Gear27 is shown as an external ring gear and gear 23 as an internal ring gear. Any other combination of gears may be used just so that sleeve 22 revolves at a different speed 0 than shaft 2.

At 28 is shown a shoulder or thrust bear ates with gear 47, shaft 48, gear 49, and gear sleeve 22 which 'is its. speed as it comes into ing, secured to sleeve 22, and a loose collar 29 to which is secured rod 30, which at the other end is secured to control plate 31. Parts 2930-31 revolve at the same speed as shaft 2 but are limitedly'slidable longitudinally.

32 is a compression spring cooperating with control plate 31 and pressure plate 34 whlch is secured to a slidable sleeve or extension 33 of shaft 2.

Pin 35 and closed slot 36 limit the movement of extension 33 in recess 37 of shaft 2.

Compression spring 38 between control plate 31 and loose collar 39, balances the pressure of spring 32. Attached to loose collar 39 1s rod 40 having adjustable stops 41 and 42 for limiting the extent of the action of the gear 12 as later explained.

Loose collar 39 cooperates with nut 43 which travels on a thread on shaft 2 and is turned by the feathered tube 44.

Tube 44 is secured to collar 45, loose on shaft 2 but having a gear 46 which cooper- 50. which is secured to bevel gear 14. 7 Nut 43 revolves faster or slower than shaft 2 according as" to whether one or the other of clutches 1719 or 20-18 is engaged. When neither clutch is engaged and the control plate 31 is in the central or'neutral position, as shown in the drawing, nut 43 rotatcs at the same rate as shaft 2. Y Secured to control rod 30 is a rack 51 hav- 7 ing three notches 52-52-52, corresponding to the three positionsof control plate 31 and sleeve-22.-

Cooperating with notches 52-52-52, is

wheel 53 carried by arm 54 pivoted at 55, to

frame 11. and cooperating with compression 1 spring 56. This device is to secure quick 30 and positive clutch action responsive to movement of control plate 31. i I

WVe' will suppose the airplane to increaselevel flight at the top of its climb. 1.

The air pressure on PIGSSl re plate 34 compresses spring 32 and moves control plate 31 to the left. Clutch 17-19 is now engaged and the engine power acting through shaft 2 and frame 11,carries gear 12 around and the reaction of gear 13 causes 12 to revolve on its axis, and through the train of gears turns shank 5 and brings the pitch of the blade up to an angle proper for the speed at the moment pertaining. At the same time nut 43 moves to the right and compresses spring 38 until pressure on spring 38 balances air pressure on conical pressure plate 34 and spring 32. This balancing of the springs acting against control plate 31, returns 31 to neutral position and discngages the clutch.

A decrease of speed. such as a steep climb, causes the air pressure on pressure plate 34 to decrease and release some of the pressure on spring 32. Spring 38 now being stronger moves control plate 31 to the right engaging clutch 20-4 8. gear 12 revolves in the opposite direction and lowers the angular pitch of the propeller blade. At the same time nut 43 moves toward the left dccreasing't-he pressure on spring 38 and restoring the balance, whereupon the control plate returns to the neutral position, disengaging the clutch.

Should the speed be still further decreased, approaching a stall. or hanging on the propeller, the pitch is still further reduced; until stop 42 contacts plate 31 and returns itto neutral position. This happens at a predetermined pitch which gives the maximum thrust for steep climb or take off.

In the other direction stop 41 contacts plate 31 when the maximum predetermined pitch for the particular engine, or blade installation is reached.

Many other arrangements of the elements of the combination as described are possible, some of which require a smaller number of parts, but all of which require the essential elements which constitute the invention.

I claim:

1. An automatic variable pitch propeller, comprising; a shaft, a hub secured to said shaft, a propeller blade shank rotatably s ecured to said hub, means for rotating said shank. cooperatively with said shaft, in reverse directions relative to said hub, control means comprising a pressure plate, a control plate, a feathered nut, and balancing springs, said control means cooperating with said reversible shank rotating means.

2. A propeller shaft, a propeller hub secured to said shaft, a propellerblade shank cooperating with said hub, operative means combining controlled power for rotatin g said shank in reverse directions relatively to said hub, control means combining a control plate,

compression springs cooperating with said control. plate, a pressure plate cooperating with one of said springs, aunovable nut, relatively positioned conformatively with said shank, cooperating with the other said spring; means limiting the extent of application of said power m reverse directions to said shank,

3. A propeller shaft, a hub secured to said shaft, a propeller blade shank coaxially rotative relatively to said hub, a control plate longitudinally slidable on said shaft, balance springs cooperating with said control plate, a fluid pressure plate cooperating with one said spring, a traveling nut cooperating with the other said spring, means using engine power for rotating said shank in reverse d1- rections, means cooperatively associating said control plate with said rotating means for controlling the application of power in revcrse directions to said shank, means limiting the extent of application of said controlled power to said shank.

4. A propeller shaft, a radially positioned propeller hub secured to said shaft, a propeller blade shank rotativcly associated with said hub, means combining engine power controllably transmitted for rotating said shank relatively to said hub, n'leans for controllably reversing the power transmission means for rotating said shank in reverse directions relatively to said hub, control means comprising opposing balance springs cooperating with said reversing means, a fluid pressure plate cooperating with one of said balance springs, means cooperatively asso ciated with said shank rotating means for compressing the other said balance spring relatively to the angular displacement of said propeller shank, means limiting the application of controlled power in reverse directions to said propeller shank.

5. A propeller shaft, a hub secured to said shaft, a rotatable propeller blade shank cooperating with said hub, rotative means for said shank comprising gearing reacting against a non-rotative part, reversing means comprising controlled clutches cooperating with said shank rotative means and a control mechanism, said control comprising balancing springs cooperating with a fluid pressure plate and a splined nut positionably controlled by said rotative means, said balancing springs cooperating with a control plate, shank rotation limiting means comprising a sliding rod cooperating with said splined nut and stops on said rod cooperating with said control plate.

CHANDLEY WILLIAM LAMBERT. 

